1. Field of the Invention
Present invention is directed to a method and apparatus for forming a film-covered flange. More specifically, the present invention is directed to providing a core with a moveable slide that overlies a flange portion of the film to form the film-covered flange.
2. Description of the Related Arts
It is also known to manufacture molded articles using flexible films wherein the film is placed within a mold and a polymer is injected behind the film to heat and soften the film backing. The film backing fuses to the polymer to form a molded article. An example of this type of method is taught in U.S. Pat. No. 3,668,034. One difficulty in manufacturing molded articles using pre-molded flexible films, is properly positioning the flexible film within the mold so that it is free of wrinkles or creases and is precisely positioned in the cavity to register with the contours to form the desired article. Heretofore, proper placement of the pre-molded film within the cavity has been a major stumbling block to widespread application of pre-molded films. The problem is especially acute when handling pre-molded thin films for large automotive applications such as bumper facias. The entire surface area of the film must be properly positioned within the cavity to produce a defect-free article. Slight misalignments will cause wrinkles or defects and make the article unusable.
It is necessary to precisely place the film between the operable core and cavity pieces of a molding press. Because these operable pieces open and close, it is advantageous to provide a mechanism which allows the pre-molded film to be robotically placed within the mold cavity rather than manual placement by an operator. It is a further desired result of the present invention to utilize existing equipment for removing the molded article from the core in the method for placing the pre-molded film within the mold. It is also desired that the method and apparatus utilize existing molding equipment to the maximum extent possible. This includes utilizing a mold press and core with a limited opening there between. It is further desirable to manufacture an article having a flange in a tool that is subject to "die-lock" conditions. Die-lock conditions occur when either the mold cannot be opened or when the part cannot be removed from the mold.
It is desirable to form articles with flange portions. The flange acts as a mechanism to attach the article and to provide the article with additional strength or rigidity. When used in exterior automotive applications such as bumper facias, the flange is abutted an adjacent component. A portion of the flange remains visible. The appearance of the flange should match that of adjacent components. In most cases, these flange portions are painted to match the rest of the facia. A difficulty arises when manufacturing these components using a pre-painted film. The film must wrap around the flange.
It is known to form a covered edge using in-mold films. An example of this construction is illustrated in U.S. Pat. No. 5,599,608. A film having a re-entrant edge portion is placed within a mold. A mold is moved to contact the core. The core engages the re-entrant portions and folds them within the mold cavity. Molten plastic is injected into the mold cavity and the combination of closing the mold combined with the pressure of the molten plastic material forces the re-entrant edge portions against the mold wall to form the covered edge of the molded article.
The method described in U.S. Pat. No. 5,599,608 is limited to forming an edge portion having a width equal to the thickness of the substrate. This is useful when forming a part having a covered edge, but not useful when forming a part having a covered flange. A flange requires a space behind it. This space is known as an undercut. The 5,599,608 patent does not teach forming parts having an undercut.
It is also known to include pins or slides in the core to assist in removing the article from the mold. The plastic forms around the pin or slide and the article remains with core when the press is opened. What has not been shown, is the use of a slide to provide both an undercut and to assist in removing the article from a mold.
These deficiencies and problems are overcome by the present invention.